Ringworld (Ringworld #1)

FOUR TRAVELERS COME TO THE RINGWORLD...
Louis Wu - human and old, old; bored with having lived too fully for far too many years. Seeking a challenge, and all too capable of handling it.
Nessus - a trembling coward, a puppeteer with a built-in survival pattern of nonviolence. Except that this particular puppeteer is insane.
Teela Brown - human; a wide-eyed youngster with no allegiances, no experiences, no abilities. And all the luck in the world.
Speaker-To-Animals - kzin; large, orange-furred, and carnivorous. And one of the most savage life-forms known in the galaxy.
Why did these disparate individuals come together? How could they possibly function together?
And where, in the name of anything sane, were they headed?